Military and civilian vertical take off aircraft, such as helicopters and jump jets, spend a part of flight time in a hover condition. In some cases, the aircraft is hovering over unprepared surfaces with few references to maintain a desired altitude. Providing altitude references or cues to the pilot of the aircraft, historically, has been limited to analog dials on board the aircraft with varying scales and resolution. Some graphical displays have been developed, yet these fail to provide the resolution in altitude to be of practical use.
Thus, there is a continuing need for a display that indicates a selected hover altitude and the difference between the current altitude of the aircraft, and the selected hover altitude. There is also a need to provide a display that graphically illustrates the current position of the aircraft with respect to a selected hover altitude. The hover altitude deviation display should be able to display the selected hover altitude and the difference between the selected hover altitude and the actual altitude of the aircraft as well as display graphically the position of the aircraft, above or below, the selected hover altitude within limits selected by the pilot or designed in the display system.